Method for $1/Watt Solar Panels Will Soon See Commercial Use 502
An anonymous reader writes "A method developed at Colorado State University for crafting solar panels has been developed to the point where they are nearly ready for mass production. Professor W.S. Sampath's technique has resulted in a low-cost, high-efficiency process for creating the panels, which will soon be fabricated by a commercial interest. 'Produced at less than $1 per watt, the panels will dramatically reduce the cost of generating solar electricity and could power homes and businesses around the globe with clean energy for roughly the same cost as traditionally generated electricity. Sampath has developed a continuous, automated manufacturing process for solar panels using glass coating with a cadmium telluride thin film instead of the standard high-cost crystalline silicon. Because the process produces high efficiency devices (ranging from 11% to 13%) at a very high rate and yield, it can be done much more cheaply than with existing technologies.'"
Re:13% is considered "high efficiency" now? (Score:5, Informative)
Cost/Benefit Analysis (Score:5, Informative)
Basically, it looks like, if they last a couple years, they would pay for themselves (166 days of full utilization, but that's not going to happen in the real world). Not bad. If they're durable (and last 5-10 years), they could really cut down on electric costs.
Oh, plus the whole saving the planet from destruction thing. I guess that might have some value.
Re:$4 / watt current prices? Where? (Score:3, Informative)
http://www.solarpanelstore.com/solar-power.large-solar-panels.solarworld_sw.sw_165.info.1.html [solarpanelstore.com]
Re:$4 / watt current prices? Where? (Score:3, Informative)
http://www.backwoodssolar.com/catalog/solar_panels.htm [backwoodssolar.com]
The SW165 is just under $5 per watt, and many are between $5/w and $6/w
To answer your question about a 100w panel for under $800, the MF125UE (125w for $690) seems to be one.
Re:Simple conversion (Score:5, Informative)
Re:Batteries (Score:3, Informative)
Your Heavy Metal Atmosphere (Score:3, Informative)
Re:watts per what unit of time? (Score:3, Informative)
Watt is a per-time unit. 1 Watt = 1 Joule per second.
A watthour is a 1 watt, sustained for an hour; a kilowatthour 1000 Watt, sustained for one hour.
"Watt per minute" doesn't make sense, except when talking about things like a change in power.
Re:So, how many watts per sq. meter ? (Score:5, Informative)
It did mention efficiency, so you can calculate it. Find an insolation map [wikipedia.org], find your location on it, find the average kWh/day you get, and multiply by the 11-13% figure mentioned in the article.
Interesting (Score:5, Informative)
1.5 to 2 KW worth of panels is enough to run a typical house unless you have a machine room. Even if you use more power then your panels can produce, it's actually all to the good because it means the panels are recovering the highest-tier electricity costs for you, dropping you down to a lower tier with your utility company.
You don't want batteries unless you are off-grid, and most people will be on-grid. There are many grid-tie solutions available and costs have come down considerably over the years. Batteries are of course essential if you are off-grid but knowing the many hackers here I'm sure many of you would like to be able to disconnect from the utility completely, survive blackouts, and so forth... but generally speaking, the batteries and equipment required to do that adds a lot to the cost of the system and involve considerably more maintenance and worry.
A straight grid-tie system is completely maintenance free. I literally have not had to touch my system since the day it was installed. I just pop into the garage and stare at the cumulative power display every so often
http://apollo.backplane.com/Solar/ [backplane.com]
-Matt
batteries are still a HUGE problem (Score:4, Informative)
If we take 10% of 250 we get 25 watts. This is about as much as a high efficiency mini florescent uses.
To run a toaster we will need 40 square meters of solar panel and to roast a turkey and cook on top of the stove as well we look at 40 amps @ 240 volts (check your main panel folks) which is about 385 square meters at 25 watts per square meter.
Thing is that we might want to roast the xmas turkey after dusk, so we better plan on batteries.
A deep cycle 12 volt battery (lead acid) can be expected to hold 60 amp-hours.... at least this is what the Hawker batteries I use for my UPS system are rated for.
12*60 = 720 watts hours. To roast the turkey say takes 4 hours at a draw of say 30% of 40 * 240 which is about 11,250 watt hours. So we need 15 batteries for this. Next if we draw them down any more than about 20% the number of cycles goes into the toilet so we'll need about 5x as many so we can draw each to about 20% of their max rating. We'll need 75 batteries.
New these batteries cost more than $250 bux so that is a battery investment of $18,750.
Clearly one will not be running an electric range off that solar system.
I'm not scoffing at the idea. I think its good but one has to find a way to store that energy and perhaps the best use of it will be to create hydrogen.
The thing is that sure it can feed into the grid during the day. All this does is put idle the current generating infrastructure and we still need that infrastructure for night operation. Of course it would save the fuel needed to operate the plant.
But then what would we use the existing generating stations for when they are idle? Generating hydrogen?
Somehow it doesn't make sense to burn fuel to create electricity to make hydrogen when we can simply for instance chemically take the Methane apart and get hydrogen that way.
One really has to think about how this cheap solar technology fits into the full cycle of energy needs.
Nevertheless I think it is good and maybe we should use it to pump water up hill. Then at night we can let the water flow back through the pump and turn it into a motor-generator. Batteries are just one way to store energy. It can be stored as compressed air, water at the top of a hill, chemically such as hydrogen gas... but it will need to be stored and in great quantities if this technology is going to go anywhere.
Plants such as trees are another good solar collector. We tend not to use them. They are reasonably efficient and serve as their own battery system because if you need more heat you can chuck another log on the fire. Since most of us tend not to use the solar collectors mother nature already created for us, I suspect that there will be huge issues to overcome in order to deploy even cheap man-made ones.
Now here is another thought. The best efficiency of these collectors is say 10%. If we capture the same energy for space heating our houses we can easily get over 80%. Yet, most of us do not even do this.
A super heated house with R70 in the ceiling and R50 in the walls costs about $1 dollar per square foot of building envelope extra during construction. This will eliminate the vast majority of summer cooling and winter heating loads. Here in Calgary for instance a house like this does not need a furnace and we can have winter days that are 40 below for weeks on end. A house like this can get by with a nice fireplace and wood heat and will burn less than 1 cord of wood per year. That wood costs about $100 dollars.
But, most of us don't even do this.
I think solar is a great idea but a low
Re:13% is considered "high efficiency" now? (Score:5, Informative)
-Matt
Re:cadmium telluride thin film on glass... (Score:1, Informative)
(This results for example in a much lower boiling temperature for Cd when compared to CdTe.)
Re:So, how many watts per sq. meter ? (Score:2, Informative)
Sorry, but 60% is not the world record. The world-record in efficiency is currently about 42.8%, held by the University of Delaware. Here's their press release [udel.edu].
However, the most efficient cells in production for commercial use are from Spectrolab [spectrolab.com], a Boeing subsidiary. They claim 40.7% as of December 2006 - which was the world's record until UD broke it 23 July 2007.
According to Spectrolab's web site, the cells they're producing for distribution include their Ultra Triple Junction [spectrolab.com] cells, with a minimum efficiency of 28.3% and a typical terrestrial efficiency of 31% claimed.
In their FAQ [spectrolab.com], they claim that a concentration of 500 suns is typically optimal. On the earth, you then have to deal with the fact that 2/3 of the energy is not turned into electricity - which means a significant amount of heat to deal with. You would want to cool the cell with something, lest it burn up. Their FAQ mentions that using a 1 cm^2 cell, at 500 suns and 25C will produce about 17.5W - so you'd be "spending" at least 500 cm^2 of real estate to prodcue the 17.5W : 500 cm^2 for a Fresnel lens [wikipedia.org] to focus it down to 1 cm^2 on the cell.
I think they'll sell to anyone as long as you're a U.S. citizen and agree to the export limitations. However, they have a minimum purchase of $5,000 - but you must spend more to get optimal pricing.
Well. My point is this: 60% is not what anyone's achieved. Most companies are just trying to get their $/Watt price as low as possible in order to get widespread acceptance - instead of attempting a new world-record.
I wish that someone had gotten to 60% - it's 2/3 of the way to the Carnot limit of 95% If you're referring to these guys [evidenttech.com] and their "quantum dot cells", from their web site you'll see that it's still all theoretical.
BTW - you can buy a plastic Fresnel lens here [edmundoptics.com], unless they've changed the web page. Be careful and wear a welding helmet (or equivalent) so that the intense concentration of sunlight on something won't be able to cause a light bright enough to burn your retina.
You Borked the math (Score:4, Informative)
Now this hocus pocus about the after tax situation is wrong too. If you want to include that then you have to include it on the 8000 dollars as well so Since the 8000 cost is after taxes, there's no point in calling the return on investment after taxes. Or if you want to then it costs 12300 of pre-tax income to buy the 8000 panels.
The ROI is negative since 437 electricity minus 640 interest is a 200 loss every year.
Re:cost benefit analysis (Score:5, Informative)
Re:cost benefit analysis (Score:5, Informative)
--
Rent solar power for your home and save: http://mdsolar.blogspot.com/2007/01/slashdot-users-selling-solar.html [blogspot.com]
Re:Back of the envelope (Score:3, Informative)
What does it matter? (Score:3, Informative)
Re:Simple conversion (Score:3, Informative)
http://www.pages.drexel.edu/~brooksdr/DRB_web_page/papers/UsingTheSun/using.htm/ [drexel.edu]
According to ASHRAE, a horizontal surface on the earth will get around 256 btuh/sq ft peak at noon on a clear, sunny day. By my calcs, that's about 800 Watts/sq meter.
For yesterday's data on actual insolation at the surface in the Western US, see this:
http://www.soils.wisc.edu/wimnext/insol/westinsol.html/ [wisc.edu]
Here's a little more on the subject:
http://www.solar4power.com/solar-power-insolation-window.html/ [solar4power.com]
http://rredc.nrel.gov/solar/old_data/nsrdb/redbook/atlas// [nrel.gov]
Re:Interesting (Score:5, Informative)
Like you, I have a residential grid-tied system. The panels cost roughly $5/kW, plus a similar amount for the inverter, installation, etc., and I decided it was a reasonable investment if the lifetime of the panels was 25 years. If the panels only cost $1/kW, then the whole thing would have been a reasonable investment even if the projected lifetime of the panels was 5 years. Actually I find it a little frightening to have so much of my money tied up in this physical object sitting on my roof. It's covered by insurance in case of an earthquake, etc., and by warranty under some other conditions, but in general, if someone offered me a system with much cheaper panels, and told me I might have to get them replaced more often, I would probably prefer that, because it would tie up less of my capital in the system.
This may vary from place to place. I live in Southern California, and my electric company is SCE. The way the deal here works, it's a really bad idea to pay for a system that generates more in a year than you use in a year. SCE bills me yearly. If I generate a little less than I use, they send me a small bill at the end of the year, which is fine. (If you realize you're consistently generating less than you use, you can always add more panels later, assuming you have the roof space. You've already invested in the inverter, so it's not a big deal to add more capacity.) If I generate more than I use, then they don't send me a check, they just say, "Thanks for the free electricity." If I overproduce, it means I goofed big-time, because I spent more money than I needed to on my system, and it isn't returning any more on my investment than a smaller system would. Basically if you do things right, you end up with something that almost exactly covers your yearly electricity, and that means you couldn't care less what the rates are on your schedule (schedule D, TOU, whatever) -- when you pay zero, you don't care what rate you're paying at.
Re:13% is considered "high efficiency" now? (Score:5, Informative)
However, that's actually not relevant to the main issue. You don't want to live close to the edge. You want to be sure you have capacity for when you need it. But you also want your batteries returned close to full by the end of the day to provide your power needs that night and into the next run of cloudy days. So you have to provide enough solar wattage to make sure you do that most, if not all days. Or you need to have an alternate power source for peaks (like a generator.) But most solar people don't want to use a generator.
Anyway, point is on the many days when you use less than capacity and the batteries are fully charged, you are just throwing away the power when the batteries are full. That's not the green thing to do. Certainly the people who go off-grid on a property connected to the grid are being foolishly non-green. The grid provides both a way to get any excess power you need during low solar periods, and a way to make sure all the power you generate goes to good use. That's why government rebates etc. only apply to grid-tie solar installations.
Re:Back of the envelope (Score:3, Informative)
Re:Back of the envelope (Score:3, Informative)
Doesn't have to be break-even. Most people don't buy the most efficient vehicle that will meet their needs, they go larger. Decisions are not always purely economic.
Of course, how much value an individual puts into being green or grid-independent varies, so it's tough to calculate. Solar panels, perhaps unfortunately, aren't as sexy as hot cars.
Still, solar has made sense in a number of remote locations for years now, where it's just too expensive to run a power line out into the boonies.
Re:4 square feet of glass is $17.40 in the store (Score:3, Informative)
Re:Back of the envelope (Score:2, Informative)
Ferretman
That's if you're up in space (Score:4, Informative)
- Night (50% averaged for the year).
- Suboptimal angling on the panel relative to the sun throughout the day (guessing pi/4 since I'm too lazy to do the integral).
- Weather (highly dependent on location but this report [agci.org] says 54% in the northern hemisphere, let's use 30% to account for light that manages to get through the clouds).
- Panel efficiency (12%).
- Conversion losses. I should be including losses converting solar panel DC into the AC most household appliances use, but let's be optimistic and say these panels spur development of DC appliances.
- Battery efficiency. Unless you plan to use your lights only during the day, you're going to have to store electricity for night use. Lead acid batteries are about 90% efficient. Wild guess, but say a half of your daily electricity use will be drawn off the batteries, yielding an average 95% battery efficiency. Yeah you could draw electricity off the grid at night, but since we're hypothesizing DC appliances and throwing away conversion losses, I think this is the smaller of the two.
Phew. So what do we have? 1600 W/m^2 * 0.5 (atmosphere) * 0.5 (night) * pi/4 (angling) * 0.7 (weather) * 0.12 (panel) * 0.95 (battery) = 25 W/m^2. That's probably a more realistic figure to use if you want to calculate how much electricity use the panels will save you over a year. The average U.S. home consumes about 1 kW (averaged over the year), so to completely take each home off the grid would require about 40 m^2 of panels. You'd probably want more than that to get you through the Winter months and long bouts of bad weather, but that's very location-specific. We'll just use 40 m^2 and calculate a minimum.Assume the $1 per Watt figure is under ideal conditions (companies love to do that). 800 W/m^2 * .12 = 96 W/m^2. So a square meter of this stuff will run you $96. Multiply by the required 40 m^2 to yield $3840 per home.
Figure an average electricity cost of $0.13 per kWh (in the higher priced areas where this stuff will be used first). Average home burning 1 kW (yearly time-average) would thus spend 24*365*1 kWh = 8760 kWh for the year. At $0.13 per kWh, that's $1139/yr in electricity costs. Ignoring installation labor, the panels would pay for themselves in 3 years and 4.5 months at earliest. Adjust up depending on your latitude and weather. Adjust down if you aren't as power-hungry as homes in the U.S.
I think we have a winner.
Re:cost benefit analysis (Score:3, Informative)
Just for clarity for those who don't know:
Watts are a rate of flow for Joules.
Joules are a unit of energy (kg m^2 / (s^2)) which describe the distance (m) that a force (kg m/(s^2)) is applied over
99% efficiency in a transformer means that converting a low voltage, high current source to a high voltage, low current source producing the SAME WATTAGE or the SAME ENERGY when INTEGRATED OVER TIME, only a fraction of a percent is lost in the generation of heat due to resistance, unencapsulated EM field, etc.
An inverter converts Direct current (DC) to alternating current (AC) and is necessary for AC transformers because a solar panel will typically produce DC output and transformers respond to changes in a magnetic field, rather than the present state of it.
Re:13% is considered "high efficiency" now? (Score:2, Informative)
With 3.4 billion years of evolution behind photosynthesis, plants have managed to do a bit better than that. According to this wiki [wikipedia.org] plants are very efficient:It will take humans quite a while to improve on the efficiency of the houseplant. But then again, plants aren't turning sunlight into electricity.
Re:May not be for real. Wait for pilot plant. (Score:2, Informative)
Re:It makes me kinda wonder how (Score:3, Informative)
In the developed world we have substituted materials that did not require so much energy for ones that do. To follow your line of reasoning consider the can opener in your kitchen and compare it with your grandmothers first canopener. Heres was a carbon steel blade, she might have even had the knife sharpener man who came by sharpen it from time to time. it was probably made in chicago or some place near a train depot. Yours is a plastic handled item, with a more refined steel and coated with more advanced metals. It was made in china from materials shipped from many different places, then wrapped in paper and plastic to hang in your brightly lit store. It's disposable. It's cheaper too because substituting energy for man power and materials costs have made it so. But it uses orders of magnitude more energy to make and get to you than your grandmothers.
Look at your couch. Heres was an oak frame, made to be reupholstered many times over it's life. It was filled with cotton batting and covered in cotten or flax. Yours is a particle board, metal and plastic frame. It was made mainly by robotic tools. And it is filled with oil based poly filled and covered with synthetic fibers all of which are treated. It too was made far away and shipped. it is disposable.
Moreover, your couch has more than 300% more materials in it since it's at least 40% bigger in every dimension. Indeed everything in your house is bigger. Your bed is bigger, your chairs are bigger. your doorways or bigger. IN fact house sizes are growing.
Every year we build more and more square footage of houses and apartments. That's both for people who are increasing their sq footage and for all those new people. And when we tear down and replace old houses, the new house require more energy per sq foot than the old one. We build wider roads and more exotic infrastructure under them as time moves on. Everything is the sort of analogous to how it was but so much more sophisticated and made from much more energy intensive materials.
So I think perhaps that answers your question.
As a rule of thumb, over a short period of time the gross domestic product is proportional to energy consumption. But over the long haul the pre-factor in the proportionality is also increasing as well.
The bottom line is that it's not enough to say I have the same sort of household my parents did. As the population rises we may have to actually use less energy individually just to stay even.